Tags: Locomotive.
The 3521 Class were forty tank locomotives designed by William Dean to haul passenger trains on the Great Western Railway. They were introduced as 0-4-2T locomotives in 1887 but were quickly altered to become 0-4-4Ts to improve their running. Following two serious accidents they were further altered from 1899 to run as 4-4-0 tender locomotives in which form the last was withdrawn in 1934.